add: more specs, all_*_squares
add: color & formatting to spec task
add: missing require
mod: change action values

Used to be uppercase strings ("FORWARD"), now lowercase symbols
(:forward).
fix: wumpus detection works for stench/no stench
fix: pathfinding uses only visited squares and the target square
fix: Expedition executes actions in correct order
fix: Expedition is cancelled if hunter senses a bump
fix: Exploration issues appropriate actions

All actions have been replaced by :shoot during a careless
find-and-replace.
rea: comment out debugging output
add: Exploration logs
add: Exploration specs
add: Hunter, Expedition logging
fix: consecutive Expeditions possible

The issue was: Expedition 1 has to be cancelled because of bump;
Exploration decides new Expedition 2; Expedition 2 still senses the
same bump and has to be cancelled; repeat as often as unnecessary
add: Exploration specs